Enhancing the rate of ex situ mineral carbonation in dunites via ball milling

The investigation of potential options for CO2 sequestration is of vital importance for alleviating the ongoing climate problem. This paper presents an efficient method for enhancing the ex situ carbonation of dunites. The ball milling process was applied to a dunite from the Troodos ophiolite (Cyprus), in order to create a new type of material with enhanced CO2 uptake. Through CO2 chemisorption followed by temperature-programmed desorption (CO2-TPD) experiments, optimum ball milling conditions were found (12 h of wet ball milling with 50 wt% ethanol as process control agent), leading to an increase of CO2 uptake of dunite by a factor of 6.9. A further increase of CO2 uptake by 10% was accomplished after 4 h of additional ball milling with smaller balls. Additionally, CO2-TPD along with in situ DRIFTS studies indicated that the CO2 uptake of the dunitic materials can be substantially enhanced by the presence of H2O during CO2 chemisorption. The positive effect of H2O on CO2 chemisorption becomes much more evident after the ball milling process. Specifically, the CO2 uptake of the ball-milled sample (BM45) was enhanced by a factor of 5.8 (from 181.9 to 1047.5 μmol g-1), when CO2 chemisorption was performed in the presence of 20 vol% H2O. © 2016 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved

Design, assembly and characterization of silicide-based thermoelectric modules

Silicides have attracted considerable attention for use in thermoelectric generators due mainly to low cost, low toxicity and light weight, in contrast to conventional materials such as bismuth and lead telluride. Most reported work has focused on optimizing the materials properties while little has been done on module testing. In this work we have designed and tested modules based on N-type magnesium silicide Mg2(Si-Sn), abbreviated MGS, and P-type Higher Manganese Silicide, abbreviated HMS. The main novelty of our module design is the use of spring loaded contacts on the cold side which mitigate the effect of thermal expansion mismatch between the MGS and the HMS. We report tests carried out on three modules at different temperatures and electric loads. At a hot side temperature of 405 °C we obtained a maximum power of 1.04 W and at 735 °C we obtained 3.24 W. The power per thermoelectric material cross section area ranged from 1 to 3 W cm-2. We used the modeling tool COMSOL to estimate efficiencies at 405 and 735 °C and obtained values of 3.7% and 5.3% respectively - to our knowledge the highest reported value to date for silicide based modules. Post-test examination showed significant degradation of the N-type (MGS) legs at the higher hot side temperatures. Further work is underway to improve the lifetime and degradation issues. © 2015 Elsevier Ltd

Design, assembly and characterization of silicide-based thermoelectric modules

International audienceSilicides have attracted considerable attention for use in thermoelectric generators due mainly to low cost, low toxicity and light weight, in contrast to conventional materials such as bismuth and lead telluride. Most reported work has focused on optimizing the materials properties while little has been done on module testing. In this work we have designed and tested modules based on N-type magnesium silicide Mg2(Si-Sn), abbreviated MGS, and P-type Higher Manganese Silicide, abbreviated HMS. The main novelty of our module design is the use of spring loaded contacts on the cold side which mitigate the effect of thermal expansion mismatch between the MGS and the HMS. We report tests carried out on three modules at different temperatures and electric loads. At a hot side temperature of 405 °C we obtained a maximum power of 1.04 W and at 735 °C we obtained 3.24 W. The power per thermoelectric material cross section area ranged from 1 to 3 W cm-2. We used the modeling tool COMSOL to estimate efficiencies at 405 and 735 °C and obtained values of 3.7% and 5.3% respectively - to our knowledge the highest reported value to date for silicide based modules. Post-test examination showed significant degradation of the N-type (MGS) legs at the higher hot side temperatures. Further work is underway to improve the lifetime and degradation issues. © 2015 Elsevier Ltd

Key properties of inorganic thermoelectric materials - tables (version 1)

This paper presents tables of key thermoelectric properties, which define thermoelectric conversion efficiency, for a wide range of inorganic materials. The twelve families of materials included in these tables are primarily selected on the basis of well established, internationally-recognized performance and promise for current and future applications: tellurides, skutterudites, half Heuslers, Zintls, Mg-Sb antimonides, clathrates, FeGa3-type materials, actinides and lanthanides, oxides, sulfides, selenides, silicides, borides and carbides. As thermoelectric properties vary with temperature, data are presented at room temperature to enable ready comparison, and also at a higher temperature appropriate to peak performance. An individual table of data and commentary are provided for each family of materials plus source references for all the data. © 2022 The Author(s). Published by IOP Publishing Ltd